According to the unsourced report, the show was having a “mini workshop” this week at the Public Theater in New York, and a full-scale workshop is being planned for March 2017. The report said “producer Scott Rudin is involved, so if the reviews are good, it’s sure to move to Broadway, perhaps by the spring of 2018, when the composer will celebrate his 88th birthday.”

Mantello has a long Broadway resume of plays and musicals, notably the blockbuster Wicked, the 2004 revival of Sondheim’s Assassins, plus the 2016 Tony-winning Best Play, The Humans. Mantello himself won Best Director Tony Awards for Take Me Out and Assassins.

Representatives for the Public Theater told Playbill.com earlier this year, “We are happily developing the Buñuel project with Stephen Sondheim and hope to present it in the near future but no set date has been confirmed.”

The Public Theater representatives did not immediately return Playbill.com‘s request for confirmation of the new report.

The project, Sondheim has previously revealed, is in two acts, the first based on Buñuel’s The Discreet Charm of the Bourgeoisie (1972), the second on The Exterminating Angel (1962), both set at surreal dinner parties. The musical, Sondheim said, is about “trying to find a place to have dinner.” The first deals with interruptions to dinner, the second is about “people who have dinner and can’t leave,” which “is my cheerful view of the world today.”

Inspired by two surrealist films by Spanish director Luis Buñuel, the musical is being developed at The Public Theater—incubator of Hair, A Chorus Line, and Hamilton—under the working title Buñuel. It will be Sondheim's first new musical since his and John Weidman’s Road Show in 2008, which was also done at the Public.

The Post’s source also said, “It reminded me of [Sondheim's 1994 show] Passion, where Steve’s music flows in and out of the storyline. It’s not an old-fashioned Sondheim show — you know, song, dialogue, then a song. It’s much more seamless.”

Another source called Ives’ script “nonlinear.” Post reporter Michael Riedel wrote, ”It moves backward and forward in time. I hear it’s a bit tricky to follow on the page, but, with Sondheim’s songs, is clear and funny on the stage.”

Fans were hoping it would be ready for an Off-Broadway premiere in 2017, but the Post reports that only Act I is complete. Sondheim suggested the 2017 time frame during a talk back at the Glimmerglass Festival earlier this year.

Sondheim, whose career stretches back to the 1950s with Sweeney Todd, Into the Woods, A Little Night Music, Company, and more than a dozen more musicals, is collaborating with librettist Ives (All in the Timing).